Syncope: clinical events during loss of consciousness may have helped distinguish seizure from no seizure.

Clinical bottom line (level 4)

  1. Nearly 45% of patients with at least one transient loss of consciousness had a seizure.
  2. Patients were more likely to have had a seizure if they:
    • had a witnessed disorientation after the event (LR+5.03)
    • were biting their tongue after the event (LR+7.33)
  3. Patients were much more likely to have had a seizure if they had a witnessed blue face during the event (LR+15.5) .
Hoefnagels et al: Journal of Neurology 1991; 238: 39-43
Expires October 2004

The study

Setting: neurological department, The Netherlands

94 patients (aged mean 47 years, 51% male) one or more episodes of transient loss of consciousness. Transient loss of consciousness was defined as an episode of less than one hour with inability to maintain posture, loss of contact with the environment and amnesia for the events which occurred during the episode

Excluded if
  • epilepsy
  • due to trauma or subarachnoid haemorrhage
  • aged <15



    • Non-independent ?blinded reference standard, applied in all patients from a consecutive appropriate spectrum.
    Reference standard:
    • composite reference standard (follow-up and investigators selection of clinical criteria). seizure classified as: if an eyewitness observed more than a few movements and identified clonic movements from a range of movements imitated by the interview- if follow-up gave no reason for a change diagnosis was seizure. Any other event was classified as no seizure (syncope and related conditions)
    Diagnostic test: clinical findings and history

    The evidence

    pre-test probability of seizure: 44%, (95% CI: 34% to 54%)

    diagnostic test seizure no seizure LR+
    (95% CI)    		 post-test probability LR-
    (95% CI)    		 post-test probability
    witnessed disorientation after the event 35 9 5.03
    (2.74 to 9.24)     		80% 0.18
    (0.08 to 0.37)     		12%
    tongue biting after the event 17 3 7.33
    (2.30 to 23.3)     		85% 0.62
    (0.48 to 0.81)     		32%
    witnessed blue face during event 12 1 15.5
    (2.10 to 114)     		92% 0.72
    (0.59 to 0.88)     		36%
    total 41 53

    Citation

    1. Hoefnagels WA, Padberg GW, Overweg J, et al: Transient loss of consciousness: the value of the history for distinguishing seizure from syncope. Journal of Neurology 1991; 238: 39-43
    Contributor: Clare Wotton and Musab Hayatli, October 2000
    Reviewer:

    Clinical Question.
    Patient transient loss of consciousness
    Intervention or Exposure history, tongue biting, disorientation, pallor, blueness
    Outcome seizure or syncope